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CWE WEAKNESSES  /  CWE-93

CWE-93

Improper Neutralization of CRLF Sequences ('CRLF Injection')

Base

What it is

The product uses CRLF (carriage return line feeds) as a special element, e.g. to separate lines or records, but it does not neutralize or incorrectly neutralizes CRLF sequences from inputs.

Impact

IntegrityModify Application Data

Mitigations

  • [Implementation] Avoid using CRLF as a special sequence.
  • [Implementation] Appropriately filter or quote CRLF sequences in user-controlled input.

Real-world CVE examples

  • CVE-2002-1771 — CRLF injection enables spam proxy (add mail headers) using email address or name.
  • CVE-2002-1783 — CRLF injection in API function arguments modify headers for outgoing requests.
  • CVE-2004-1513 — Spoofed entries in web server log file via carriage returns
  • CVE-2006-4624 — Chain: inject fake log entries with fake timestamps using CRLF injection
  • CVE-2005-1951 — Chain: Application accepts CRLF in an object ID, allowing HTTP response splitting.
  • CVE-2004-1687 — Chain: HTTP response splitting via CRLF in parameter related to URL.

Related weaknesses

Test & detect

Browse all common weaknesses, check related exploited CVEs, or map to ATT&CK techniques.

Source: MITRE CWE. View on cwe.mitre.org →

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